Effects of diazepam on auditory evoked potentials of rats elicited in a ten-tone paradigm

The effect of diazepam on sensory gating was studied in rats by measuring d iazepam effects on auditory evoked potentials (AEPs) elicited in a ten-tone paradigm. Trains of 10 repetitive tone-pip stimuli were presented. Rats (n = 8) received 4 mg.kg(-1) diazepam subcutaneously or vehicle, counterbalan ced over two sessions. Diazepam decreased the amplitude of the middle-laten cy P-30 component and increased the amplitudes of the late-latency N-60 and P-67 components. The increase in the late-latency components might be due to a diazepam-induced decrease in arousal. Stimulus repetition decreased th e amplitudes of the middle-latency N-18 and P-30 components in both conditi ons. This suggests that automated neuronal recovery functions underlying se nsory gating remain intact with diazepam. In the vehicle condition, the amp litude of the late-latency P-67 decreased with stimulus repetition, but not in the diazepam condition. This suggests a diazepam-induced decrease of be haviourally mediated habituation. Copyright (C) 2000 S. Karger AG,Basel.